1-methyl-2,4-dihalogen anthraquinone and process of making the same



Patented Apr. 30, 1929.

" .1.VUNITEIDLSTATE'S PATENT orFlcaj ROGER ADAMS, OF URBAL TA,

mars, nssxenon To run nnwron'r ronn'rron or DELAWARE. j

courm, A con- 1-METHYL2,4-DIHALOGEN ANTHRAQ'UINONE AND PROCESS OF MAKING THE SAME.

NoJJrawing. Application filed April fl, 1927, Seria1 No. 186,584. Renewed October 15, 1928.

This. process relates to 1-methyl-2,4-dihalogen anthraquinones and to a process for making the same.

It is an object of this invention to provide a simple and economically practicable method for making l-methyl-QA-dihalogen anthraquinones which are of themselves valuable intermediates in the preparation of dyestufls.

Other and further aspects of this invention will be apparent from the disclosures in the specification and appended claims.

I have discovered 'that '2,4:'-dichloro-5- methyl-ortho benzoyl-benzoic acid, which has been described in my co-pending application, Serial No. 179,193, filed March 28, 1927, under certain conditions loses one molecule of water and closes, the ring to form 1-methyl-2,4-dichloro-anthraqumone. Thls reaction is probably best expressed bk he. following chemical equation in which represents a halogen atom, such as chlorine or bromine;

acid and boric acid. The fact that this reaction proceeds so smoothly is quite unexpected in view of the tendency in similar compounds for the chlorine group assuming the 4 position in the anthraquinone body formed to hydrolyze. sis of the chlorine does not take place i conditions of time and temperature are suitably controlled. 1

1-methyl-2,4-dichloro-anthraquinone is a yellow crystalline solid giving all the typical reactions of an anthraquinone of this type.

After repeated crystallizations of the compound from chloroform, I obtained a constant melting point of 155 C.

Without limiting my invention to any particular procedure, the following examples,

I v agent. It has been found that hydrolg".

f t e will serve to illustrate my invention in the preferred form:

Example 1. 1-methy Z-2,4-dicl|loro-antkraguinone. 20 parts of 2,4-dichloro-5'-meth l-orthobenzoyl-benzoic acid are dissolve in 700 parts of sulphuric acid monohydrate) and- 4 parts of boric acid. is solutionis heat ed to 100, C. and held at this temperature for two hours. The reaction product .is poured into 4000 parts of cold water. The precipitate is filtered and washed with cold. water till practically free of mineral acid. It is then dried in vacuum at'100 C. The yield .is substantially equal to that thedretically expected. The melting point on the purified product is 155 C.

, Example 2. 1-metk t Z43,4-dib701r1,o-(intll.ra.-

' gwmone.

The preparation of 1-methyl-2,4-dibromoanthraquinone may be carried-out following the procedure in Example 1., except that molecular proportions of 2',4-dibromo-5'- methyl-ortho-benzo l-benzoic acid are employed in place 0 the corresponding dichloro compound.

I am aware that many changesmay be made and numerous details of the process may be varied through a wide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent I anted hereon, otherwise than necessita by the prior art.

. I claim as my invention:

1. The process of preparing 1-methyl-2, 4-dil1alogen anthraquinones, which comprises treating 2',4-dihalogen-5' methyl-orthobenzoyl-benzoic acid at a temperature of about 100 C. with sulphuric acid as dehydrating 2. The process of preparing 1-methyl-2, 4-dichloro anthraquinone, which comprises treating 2",4-dichloro-5'-methyl-ortho-benzoyl-benzoic acid with a mixture of sulphuric acid and boric acid at a temperature of about 100 C. as dehydrating agent.

3. The process of preparing 1-methyl-2, 4-dichloro-anthra uinone, which comprises treating 2',4-dic loro-5-methyl-ortho-benzoyl-benzoic acid with sulphuric acid mono hydrate and boric acid to a temperature of 100 (3., holding at that temperature for approximately twohours,and diluting the mass 5. As a new article of manufacture, 1- 15 with water to precipitate out the l-methyl-Q, methyl-2,4-dichloro-anthraquinone, having, 4-dichloro-anthraquinone. most probably, the following chemical 4. As new articles of manufacture, 1- formula:

5 methyl-2,4-dihalogen anthraqumones, hav- 0H.

ing most probably the following chemical CO 20 formula, in which n: represents a halogen (I atom; V

0o 10 c0 CH: 9

x l In testimony whereof I have hereunto sub- 25 scribed my name at Urbana, Chempaign,

co County, Illinois.

' ROGER ADAMS. 

